Harvesting solar energy directly utilizing energy converters, such as energy converters using photovoltaic technology is currently considered as an essential component for future global energy production. Organic photovoltaic (OPV) devices are also recognized as a viable option for low-cost power conversion technology to compete with the currently existing silicon-based photovoltaic devices. However, the low power conversion efficiency of OPV devices has limited their existence in the market competitively as a stand-alone device. Integrating OPV with energy storage devices such as supercapacitors and batteries thus offer a promising alternative approach to meet the increasing power demands of energy storage systems in general. It is recognized that combining photovoltaic devices with energy charge storage devices enables applications in off-grid and low light situations and such devices are deemed essential for wide spread adoption of photovoltaic devices.
There are considerable efforts in developing photovoltaic-battery module by coupling on top of each other or side-by-side a thin film solar cell and a lithium-polymer battery. Such constructions require electrical interconnections which increase the internal mechanical resistance of the constructions and are typically not suitable for applications that need flexible substrates.
Thus, there is a need for improved integrated devices which allow energy conversion as well as energy storage.